Freewheeling clutch



M/fa 7 l Jan. 4, 1938. s. FISCHER 2,104,320

FREEWHEELING CLUTCH Filed May 13, 1956 2 Sheets-Sheet 1 I Li BY man www@ A-TTORNEY V .'lan. 4', 1938. s. FISCHER FREEWHEELING CLUTCH Filed Mayls, 1956 2 sheets-sheet 2 INVENToR STEFAN scHEn BY /fZLZ/l'm 5.

ATTORN EY Patented' Jan. 4, 1938 UNITED STATES PATENT OFFICE n Appiication May 1a, 1936. serial No. 79,450

' In Czechoslovakia May 18, 1335 18 Claims. (Cl. 192-44) My invention relates Ato afree-"wheeling clutch permitting free-wheeling and clutchingin both directions of rotation. A

An object of the invention is vthe provision lof a clutch of the said type which may be so ad- 'justed also during the operation, by means of simple shifting elements, that it may act as a free-wheeling device either in one main direction of rotation, or in the opposite direction, or that it may establish a solid clutch in both directions.

A further object of the Ainvention is the provision of means for making the engagement or disengagement compulsory`,'elasticand free of shocks, thereby reducing the noise and the wear 15, of the engaging clutch parts to a minimum.

A clutch according to my invention, comprises a driving and a .driven part one of which is provided with cam surfaces inclined with respect to the circumferential direction of the clutch. Such. cam surfaces may run out symmetrically in re 430 shifting positions, with or without the help of transmission members placed therebetween, whereby free-wheeling may be obtained in either the one or the other one circumferential direction. The clutch maybe locked by resiliently shifting neighboring jamming members on their cam surfaces towards or away from each other until jamming is effected between the driving and the driven clutch parts.

According to the invention, movable supports are provided for the jamming members, and the inclined surfaces of a number of these supports may have a constant inclination, while thesurfaces of the remaining supports may have a varying inclination whereby different lengths of way of the jamming members may be obtained through a simultaneous turning or shifting of the movable supports in the same direction. Thus, at a certain extent of the shifting or turning of the movable supports, a jamming member may F-'i remain in its jamming position for free-wheeling in one direction of rotation of the clutch, while simultaneously the neighboring jamming member is shifted 'fromsuch jamming position into the jamming position for free-wheeling in the op- 55 posite direction, whereby the clutch will be locked.

At a further simultaneousshifting of the movable supports, however, also the flrst mentioned jamming member will be moved from its jamming position beyondits-center position into the position for Athe opposite direction of rotation of the 5 clutch whereby free-wheeling in such opposite direction -is obtained. y

According to a further feature of the invention, only some of the jamming members may be provided with the aforementioned arrangement, vl0 while resilient elements arranged at one side only in a manner well known per se, may act upon the other jamming members.` In this case, the clutchA may be used as a free-wheeling mechanism in one direction, and may also be locked. 15

In the accompanying drawing, examples of embodiments of my invention are illustrated.y

Fig. 1 is a free-wheeling clutch according to the invention in section along line I-.I of Fig. 2.

Fig. 1a is a modification of the clutch illustrat- 20 ed in Fig. 1.

Fig. 2 is a view'in section along line 2-2 ofV Fig. 1.

Fig. 3 is a section along a cylindrical surface in the direction 3-3 of Figs. 1 and 7,

Fig. 4 is a similar view of another embodiment of the movable support in the direction 4 4 of Fig. 7.

Fig. 5 shows the arrangement 'of radial wedges 'as movable supports in a section at right angles 30 yto the clutch axis.

Fig.'6 is an axial section of the embodiment of Fig. 5.

Fig. -7 is another embodiment of a free-wheeling clutch in section at right angles. to the'axis 35 of rotation.

Fig. 8 is a partial section of another embodiment with wedges at both sides of the jamming member.

Fig. 9 is ya section along the cylindrical sur- 40 face in the direction 9-9- of Fig. 8.

Fig. 10 shows the arrangement of radially journaled, rotatable cams -as movable supports.

Fig. 11 is an elevation, partly in section, of the cam and the shifting rod as shown in Fig. 10, and 45 Fig. 12 is a perspective view of the free-wheeling clutch of Fig. 7. l

In the embodiment illustrated in Fig. 1, the jamming member 31, in the present case a roller, rests on the cam surface G of the driven clutch part 2. The cam surface lconsists of two portions Gl and G2 which may run out symmetrically at both sides of a radial plane .of the clutch. f Pressure members 51, 52 and abutment members 8 are arranged in .a dove-tailedA ring groove 21 55 of theV clutch part 2. The abutment members 8 are rigidly connected to the clutch part 2 by means of pins II. They are provided each with a bore extending in circumferential direction and 5 housing one end of a spring 6. The other end of each spring 6 bears against one of the pressure members 51 which are easily shiftable in the ring groove 21. The pressure members 51 bear against the roller 31. A similar pressure member 52 10 engages the opposite side of the roller 31 and is subjected to the action of a spring 1 resting upon the spring cup 9 which is guided in the bore of the member 8. This spring cup bears with a rounded surface upon a wedge surface III1 o f pin I0 (see Fig. 3) which is guided in a bore provided in the member 8 and in the clutch part 2, and is arranged parallel to the axis of rotation of the clutch. This wedge I0 is connected to a flanged sleeve I4 (see Fig. 2) which is shiftable in 'axial directionron the splined driven shaft I2 in such a manner that the position of wedge I8 may be altered in axial direction by means of a fork I5, and consequently the tension of spring 1 may be increased more or less by a shifting of the y wedge surface |01.

If the wedge I0 is so positioned that the tension of spring 1 causes the jamming member 31 to rest at the deepest point of the surface G, no jamming 'engagement will occur between the roller and both clutch parts I and 2, that means the clutch will be disengaged provided all rollers have wedges of the same structure, since the distance of the said deepest point from the inner surface of the driving clutch part I is larger than the diameter of the roller 31.

If, now, the wedge I0 is shifted in a direction opposite to that of the arrow in Fig. 3, the tension of spring 1 will be released and r'oller 31 will be shifted to the cam surface G3 by the action of spring 6, whereby this roller approaches the inner surface of the driving clutch part. Spring 1 serves as a resilient counter-support, and, consequently, roller 31 will be elastically brought into the jamming position between the clutch parts I and 2 upon a further shifting of the wedge I0. If, in this case, the driving clutch part I rotates in the direction of the arrow S, the jamming engagement is maintained as long as the driving part tends to overrun the driven part 2.

If, however, the driving part I is decelerated, as for instance when the motor throttle of a vehicle \is closed to which the device is applied, then, the jamming action will be removed and the clutch operates as a free-wheeling mechanism. In certain instances, e. /g. during the shifting of the transmission of a motor vehicle, it is desirable to prevent the possibility of a jamming engagement of rollers 31. This maybe accomplished by pushing wedge I0 into the clutch by means of fork I5 and sleeve I4. Thereby spring 1 is tensioned, and the jamming member is elastically removed ,from its jamming engagement with clutch parts I and 2. Thereby, the jamming member takes such a position that no jamming I action can occur when the driven part overruns the driving part.

It has been found that the jamming of roller 31 in clutches of this type is only possible due to a small deformation of the roller. During its removal from the jamming position anv amount of work has to be delivered by spring1, equivalent to such deformation and causing a tendency of the roller to jump out of its jamming position. This, however, is elastically dampened by spring 6. 'If wedge I0 is shifted still farther into the clutch in the direction of the arrow'in Fig. 3, then the roller is moved to the cam surface G1 by a further compression of spring 1, and is brought into the jamming position with the clutch parts I and 2 upon a corresponding shifting of y the wedge I0. In this case, the driven part 2 is taken along when the driving clutch part I rotates in the direction of arrow S1. If the driving part I lags behind, the clutch acts as a freewheeling device for this direction of rotation. 10

Means may be provided for locking the freewheeling mechanism of my invention. In thev embodiment shown in Fig. 1a, there is a set of `rollers 31 with accessoria] parts, the same as in Fig. l.

In addition thereto, a second set of 15 rollers 32 is provided. Rollers y32 are under the one-sided action of springs 6 which bear against abutment members 8 connected to parts 2. No springs bear against the opposite sides of these rollers. Due to this arrangement the rollers 32 20 are always so kept on the cam surfaces G3 that they constantly engage the inner Acylindrical surface of the driving part. Consequently a jamming of the rollers 31 occurs between the clutch parts I and 2 when the driving part I overruns 25 the driven part 2, and the driven part 2 will be taken along. Rollers\31 are provided with the wedge arrangement described above, these rollers being jammed in the direction of the arrow S. lf sleeve I4 is shifted towards the driven part, that 30 means if the wedges are shifted into the clutch, springsv 1 become so tensioned that the rollers 31 are moved down the cam surfaces G1 and then up the cam surfaces G1 until they contact the inner cylindrical surface of part I whereby ap'g, jamming of these rollers takes place between both clutch parts I and 2 in the direction of the arrow S1. If, now, the driven part 2 tends to overrun part I, or the latter tends to lag behind the driven part 2, then, the jammed rollers 31 will prevent this, and consequently, rollers 32 will not leave their jamming position. Thus, the freewheeling is locked. In order todisengage'this lock, sleeve I4 with the wedges I0 is to be moved away from clutch part 2, releasing the tension of springs 1, whereby rollers, 31 are moved out of the jamming position on cam surfaces G1 through the tension of the springs 6. Upon a further shifting of the wedges I0 in a direction opposite to that of the arrow in Fig. 3, they are pushed along cam surfaces G2 as far as the jamming position between clutch parts I and 2: Then, the clutch acts again as a free-wheeling mechanism in the direction of rotation of arrow S.

The kwedges for altering the tension of the springs may also be arranged in any other suit--v able manner, for instance radially, as illustrated in Figs. 5 and 6. In these figures the driven clutch part 2| is fastened by a key upon the hollow shaft I6 while the driving part I connected for instance with the gear wheel 22 and being driven by the latter', may freely rotate with bushv ing I1 on the said shaft. The wedges 'IIII are radially arranged and guided in part 2I. They are pressed, by means of springs I8, against a 35 cone I9 which is axially shiftable within the hol- 'low shaft in the direction of the arrows. If cone I9 is shifted, wedges IIlI are more or less raised, and consequently, springs 1 become more or less tensioned. y

In order to use the clutch with free-wheeling also for the opposite direction of rotation rollers 32 are provided with a wedge device of a similar kind as rollers 31. This is shown in Fig. lIn

order, however, to avoid the applicationl oi' a 75 .spring 1 at the rollers 32.

second sleeve, the wedges |02 for rollers 32 may be provided vwith a varying slope (see Fig. 4), and may be connected to sleeve H4 (see Fig. 12); If wedges Il and |02 .are retracted from the clutch so far that the spring cups 9 just bear against the ends of the active surfaces of these wedges, a free-wheeling is possible in the direclare still in their left hand jamming position for the direction of rotation S. The correct inclinations of the 4wedge surfaces having the indicated enect `can be easily determined by figuring or trying. The pertaining position of the rollers 31, 3,2"and of the wedges I0, |02 iszillustrated in Fig. '7 and in Figs. 3 and 4.' The' locking is caused by the fact that a surface of wedge |02, parallel to the bore guiding this wedge will not effect an alteration of the tension of .the Consequently, rollers 32 remain jammed in the ldirection of arrow S while the springs 1 at the rollers 31 are compressed by the wedge surfaces of lthe wedges I being shifted in the direction of the arrow of Fig. 3, and'thus push the rollers 31 in the direction of the arrow S1 causing a jamming also in this direction. In this position the clutch is locked.

If the wedges |0 and |02 are still farther pushed into the clutch, also the springs 1 at the'rollers 32 will be compressed whereby these rollers too will be urged in the direction of arrow S1 until they are jammed between the rotating parts and 2.' In this position of the clutch parts, free-wheeling is possible also at a rotation of the clutch in the direction of arrow S1. y

As stated above, wedges I0 are so shaped that they push the associated rollers 31 into engagement with cam surfaces G1 when the sleeve I|4 is in the half-way position. Only a slight spring pressure is required for holding the rollers 31 on cam surfaces G1, because practically no relative movement of parts and 2 can occur when the clutch is in the locked position. The taper of wedges |0 is so continued towards their upper ends near4 sleeve ||4 that the thicknesses of the active portions of both wedges I0 and |02 are substantially equal in the pushed-in position of the sleeve, and, consequently, equal pressures or jammingforces are applied to both sets of rollers 31 and 32. This has for a result that .in the last mentioned position all rollers yequally participate in the transmission of the torque be.-

In view of Vsuch possibility, the illustrated structure of the wedges |0 is preferred.

With certain types of these clutches, itis ad- .vantageous to cause shiftable supports, for instance wedges. to act upon the respective springs at both sidesof the jamming members, as illustrated in Figs. 8 and 9. In these figures wedges |08 and y|09 are connected to a sleeve III. Springs 25 and 26 with pressuremembers 51 and 52 respectively are provided similarly to springs 6 and '1 of Fig. 7. Both springs have spring cups 21 in engagement with wedges |00 and |09 respectively, andthewedges-are guided in pressure members 23 and 24, substantially in the same .manner as for instance wedge I0 4of Fig. 7 is guided in member 8. In this'case, the wedge |08 acting upon the spring 25 may have a wedge surface either parallel or slightlyaslant tothe wedging surface of the wedge |09 acting upon the spring 26; f

-Instead of the wedges, other suitable means for instance rotatable cams may be used as illustrated in Figs. 10 and 1l. A cam |03 is rigidly mounted on a shaft |04 which is journaled ih the driven part. 2. The axis of shaft |04 is arranged in a plane at right angles to the axis l of the driving shaft, and tangential with respect to a certainrcircle. The diameterv of this circle Iis defined by the diameter of a shifting rod whichis shiftable in the hollow shaft |01.` Rod |06 is provided with teeth formed by ring grooves cut into the rod. These teeth are engaged by the teeth of aV small pinion |05 fastened to the interior end of shaft |04 which carries the cam |03. Rotation of the clutch does not influence the cam as long as the rod |0| is in a xed relation to the shaft |01 in axial direction. If, however, rod |06 is axially shifted in the bore of the shaft |01, then shaft |04 and consequently also cam |03 are turned clue to the engagement of pinion |05. `The movement increases or decreases, as the case may be, the tension of the springs 6 and 1 whereby roller 31 will be shifted towards or away from the cam.

The individual parts of the clutch and their relative positions may be made and arranged in various ways without departing from the essence ofthe invention.

'I'he free-wheeling clutch according to my invention operates as follows: The clutch illustrated in Figs. 1, 2 and 3 is disengaged when each wedge I0 is brought into such a posltion'that the tension of spring 1 counteracting the respective spring 6 has shifted roller 31 so as to rest at the deepest point ofcarn' surfaceG. No jamming action occurs in this position, and, consequently. no torque is transmitted from the driving Ypart to the driven part 2. In order to engage the clutch, sleeve I4, by means of fork I5', must' be moved in a direction opposite to that of the arrow' between its surfaces of contact whereupon driven part 2 will be taken along by part .I.

If, now, part 2 overruns part I, the friction force between the roller 31 and part changes its direction and assists` thetension of spring 1 to overcome the jamming force and the tension of spring 6, and to shift roller 31 back towards the deepest point of cam surface G. As soon as :thev

roller has left its jamming position, the said friction has only to overcome the difference in the tension of both springs. Consequently, no material transmission of a torque from part 2 to part takes place, i. e. the clutch is in its freewheeling i position. However-,as soon as part tends again" to overrun part 2, roller 31 .will be returned to its jamming position as described.

spring 1 has left its jamming position, the wedge may be returned to its original idling position whereby roller 31 is kept at the deepest point of cam surface G.

When the direction of rotation of the driving part I is reversed, i. e. if part I rotates in the sense of arrow S1 inFig. l, the clutch can be engaged by shifting wedge I out of its idling po-` sition in the direction of the arrow in Fig. 3. This causes roller 31 to engagey cam surface G1 and to get jammed between they latter and part I. Free-wheeling will occur as soon as part 2 overruns part I, and the clutch may be disengaged by spring 6 shifting the roller back when wedge III is moved so as to release the tension of spring 1.

'With regard to the device illustrated in Fig. 1a, at iirst rotation of the driving part I in the direction of arrow S1 will be contemplated. Starting from the position of wedge Il) in Fig. 3, rollers 31 are kept at the deepest points of their as'- sociated cam surfaces G. Consequently, no torque will be transmitted through these rollers, and the clutch is idling because rollers 32 will be forced down their associated cam surfaces G2 against the tension of their springs 6 by friction with part I. When part 2 overruns driving part I, coupling is effected throughrollers 32 returning to their jamming position under the action of their associated springs 6. Shifting of wedges II)l in a direction opposite to that of the arrow in Fig.'

3 does not materially alter the operation of the clutch except that rollers 31 are brought into the same position as rollers 32, and, thus, assist the latter in transmitting the torque when part 2 overruns part I. If, however, wedges Ill are shifted in the direction of the arrow in Fig. 3, rollers 31 are caused to climb their cam surfaces G1, and are jammed in between clutch parts I and 2 so as to couple these parts for rotation. In this position, no free-wheeling is possible in as much as rollers 32 prevent part 2 from overrunning part I.

If driving part I rotates in the direction of arrow S, coupling of parts I and 2 is constantly maintained by rollers 32 except when part 2 overruns part I. With wedges I0 in a middle position, rollers 31 are idling. With wedges I0 in their outward position, rollers 31 assist rollers 32, and with wedges I0 in their inward position rollers 31 prevent free-wheeling when part 2 tends to overrun part I.

In order to explain the operation of the device illustrated in Fig. 7, be it assumed that the driving part I rotates in the direction of arrow S and that wedges I0 and |02 are shifted to their outermost position. Then, rollers 31 and 32 will be urged by their springs 8 towards cam surfaces G2, thereby accomplishing engagement of the clutching elements so that part 2 will be taken along 'by part 'I. Free-wheeling is possible, i. e. part 2 may overrun part I. If now the wedges are pushed inward to the position of Figs. 3 and 4, rollers 32 remain in their original position because spring cups 3 of theirsprings lare not yet in contact with the slope.: of wedges |02. Con- Mtrary thereto, springs 1 of rollers 31 have been tensicned Vby wedges Il so much so that these rollers are on their associated cam surfaces G1 (see Fig. 7) and prevent free-wheeling if part 2 tends to overrun part I. When the wedges are shifted still more inward, rollers 32 are also caused to climb their cam surfaces G1. position the clutch is disengaged for a. rotation of driving part I in the direction of arrow S because the friction between the rollers and part I returns the former towards the deepest points of their cam surfaces G against the force of' climb their cam surfaces G2 before rollers 31` have left their cam surfaces G1 due to the dif- In this ference in the inclinations of the respective wedge surfaces. Consequently, part I continues to drive part 2. Free-wheeling, however, is impossible because rollers 32 are in their jamming position if part 2 tends to overrun part I. In the outermost position, finally, the clutch is adapted for free-wheeling in one direction because no torque can be transmitted from the driving part I to part 2.

The free-wheeling clutch according to the in` vention is of a simple construction and is composed of parts which may be manufactured very accurately.l It permits an easily operable lock ing of the free-wheeling by means of resilient elements, without friction and shocks, even at great differences of the revolutions of the clutch parts. Consequently, the wear of the locking parts is decreasedto a minimum. The clutch according to the pre'sent invention furthermore permits the use of the free-wheeling as well as the locking of the free-,wheeling mechanismin both directions of rotation of the clutch.

I claim:-

1. A free-wheeling clutch compring a driving part and a driven part in coa al arrangement, at least one jamming member between said parts, said jamming member having a free position and one jamming position in front and,

one jamming position behind its free position in the direction of rotation, a first resilient means arranged in front and a second resilient means arranged in therear of said jamming member whereby said resilient means counteract each other, and veach resilient means tends to urge said jamming member into one of its jamming positions respectively, a supporting member having a supporting surface for one of said resilient means, said supporting member being connected for rotation with one of said parts but movable relatively thereto, the other resilient means being supported by said last mentioned part. and means for moving said supportingimember from the outside relatively to said last mentioned part whereby the tension of said resilient means supported by said supporting member may be aitered upon a movement of said supporting member.

2. A free-wheeling clutch as claimed in claim 1 furthermore comprising atleast one second jamming member between said parts,l said second jamming member having a free position and a jamming position, and a third resilient means supported by said partlto which said sup-l porting member is connected for rotation,-said one jamming position behind said free position in' the direction of rotation, a first set of resilient means, and a second'set of resilient means, one resilient means of each set being arranged in front and in the. rear respectively, ofeach jamming member, and tending to urge the associated jamming member into oneof its jamming positions respectively, a ,rst set of externally.

controlled means for altering thetension of the first resilient means of the rst set of jamming members, and a second set ofexternally' controlled means for altering the tension of the first resilient means of the second set of jamming members.

4. A free-wheeling clutch comprising a d riving-part, a driven part in coaxial arrangement `with said driving part,.at least onejamming mem# ber between said parts; one of said parts having a. depressed cam surface on which said jamming member is adapted to move, said cam surface running out towards both sides in circumferential )direction in such a manner that the distance of its deepest point from said other part is larger, and the distance near the ends of said cam surface from said other part is smaller than the dimension of said jamming member between said parts, a first resilient means supported by said part with said cam surface, and tending to urge said jamming member towards one end of said cam surface, a movable means supported by said last mentioned part, and a second resilient means supported by saidmovable means and tending to urge said jamming member towards the other end of said cam surface, said movable means .being so constructed and arranged as to increase compression of said second resilient means when moved in one direction, and to decrease compression of said resilient means when moved in the other direction.

, 5. A free-wheeling vclutch as claimed in claim 4 having at least one second jamming member and a second depressed cam surface on said part with said first cam surface, and a third resilient means supported by said last mentioned part, and tending to urge said second jamming member in the same direction as said'yfirst resilient means urges said first jamming member.

6. A free-Wheeling clutch comprising adriving part, a driven part in coaxial arrangement with said driving part, a rst set of jamming members and a second set of jamming members .between said parts, one of said parts-having depressed cam surfaces,gone for each jamming member, each of said cam surfaces lrunning out towards both sides in circumferential direction in such a utnnhat the distance of its deepest point from a1 other partis larger, and the distance near the ends ofthe cam surface from said other part is jsmaller than the dimension of the associated jamming member between said parts, a set `oi rst resilient means, one for each jamming member, each first resilient means being supportedbry; said part with said camv surfaces, and tending to urge its associated jamming member-in one direction of rotation, a first set of movnable meansreach associated with one of the first set of jamming members, a second set of movable means each associated with one of the second set of jamming members, said movable means being supported by said last mentioned part, a set of second resilient means, one for each jamming member, each of said second resilient means being supported by one ofsaid movable means, and tending to urge its associ-ated jamming member .in the other direction of rotation, said first set of movable means being so constructed and ar'- `ranged as to alter the tension of said second resilient means of said f'lrst set of jamming members, and said second set of movable means being so constructed and arranged as to alter the tension of said second resilient means of said second set of jamming members.

7. In a free-wheeling mechanism having a driving -part and a driven. part in coaxial arrangement, the combination of I a jamming member movable between said parts on a depressed cam .surface of one of said parts, with a rst spring so arranged as to act upon ,said jamming member and to react upon said Vlast mentioned part, whereby -said spring tends to move said jamming memberl into a jamming position between one end of said cam surface and said other part, a supporting member connected for rotation with said part provided with Vsaid cam surface, and being movable relatively thereto, and a second spring arranged between said supporting member and said jamming member on the side of the latter opposite to the first spring whereby said second spring tends to'urge said jamming member into a jamming position between the other end of said cam surface and said other part, said supporting member being so shaped 'as to alter the tension of said second spring when being moved relatively to the part provided with said cam surface.

8. In a free-wheeling mechanism having a driving part and a driven part in coaxial arrangement the combination of a jamming member movable between said parts on a depressed cam surface of one of said parts, said jamming member being in a free position when in the middle portionof said cam surface and being in a jamming position between said parts when near the ends of said cam surface, with a first spring so arranged between said jamming member and said part provided vwith said cam surface as to tend to move said jamming member towards one end of said cam surface, a wedge movable at right angles to the plane of rotationgf said mechanism and connected for rotation with said lastmen-` tioned part, and a second spring between said wedge and said jamming member on the side of the latter opposite to said first spring, said second spring tending to move said jamming member -said part having said cam surface, said sleeve being axially movable in relation to said last mentioned part, and said wedge being attached to said sleeve.

10. A mechanism as claimed in claim 7 in which said supporting member is arranged radially Within said part having said cam surface, and in which anaxially shiftablecone is provided in the center of said last mentionedpart, one end of said supporting member being adapted to engage said cone, the other end of said supporting member being wedge shaped,v and said second spring sov being ysupported by said wedgeshaped end of said supporting member.

11. A mechanism as claimed in claim 7 in which said supporting member is formed as a cam, furthermore comprising a shaft journaled within said part provided with said cam surface, said cam being mounted on said shaft, and means for rotating said shaft independent `of the rotation of said mechanism.

12. A mechanism as claimed in claim 'I in whichl said supporting member is formed as a cam, furthermore comprising a shaft journaled within said part provided with said cam surface, the axis of said shaft being arranged in the plane of rotation of said last mentioned part, a gear wheel mounted on the inner end of said shaft, an axially movable shifting rod in coaxial yarrangement with said last mentioned part, said rod being provided with ring grooves, said gear wheel engaging said grooves, and said second spring being supported by said cam.

13. A free-wheeling 'mechanism comprising a driving part and a driven part in coaxial arrangement, a first set of jamming members and a second set ofgjamming members between said parts, one of said parts having depressed cam surfaces one for each jamming member, a set of first springs, one for each jamming member, each rst spring being supported by said last mentioned part, and tending to urge its associated jamming member in one direction of rotation into a jamming position at one end of its associated cam surface, a set of supportingmeans connected for rotation with said last mentioned part but movable in relation thereto, a set of second springs, one of said supporting means and one of said second springs for each jamming member of said first set of jamming members, each of said second springs being arranged between the associated jamming member on the side of the latter opposite to the associated first spring, and tending to urge its associated jamming member in the opposite direction of rotation into a. jamming position at the other end of its associated cam surface, said supporting means being so constructed and arranged as to alter4 the tension of said second springs when being moved relatively to said last mentioned part.

14. A free-wheeling mechanism comprising a driving part anda driven part in coaxial arrangement, a rst and a second set of jamming members between said parts, one of said parts having depressed cam surfaces one for each jamming member, a set of first springs and a set of second springs, one first spring and one second spring arranged at opposite sides of each of said jamming members, said first spring being supported by said last mentioned part and tending to move its associated jamming member in one direction of rotation into a jamming position at one end of its associated cam surface, a rst and a second set of cam members connected for rotation with said last mentioned part but movable in relation thereto, said second springs being supported by said first and. said secondcam members respectively and tending to move said second jamming members in the other direction of rotation into a jamming position at the other ends of said cam surfaces, said cam members being so constructed and arranged as to alterthe tension of said second springs when being movedrelatively to said last mentioned part, means for moving said first set of cam members and means for moving said second cam members relatively to said'last mentioned part.

15. A free-wheeling mechanism as claimed in claim 14 in which said cam members are formed as wedges, the first set of wedges'having-wedge surfaces of an inclination differing from that of y the second set.

16. A free-wheeling mechanism as claimed in claim 14 in which said cam members are formed as wedges, said wedges being adapted to be moved each in a direction at right angles to the plane of rotation of the mechanism, the first set of wedges having the same inclination over their entire active length and the second set of wedges having a not inclined portion and an inclined portion of an inclination differing from that of the rst set.

17. A free-wheeling mechanism as claimed in claiml 14 in which said cam members are formed as Wedges, the rst set of wedges having an inclination differing from that of the second set, and in which said moving means comprise a sleeve connected for rotation with said part with cam surfaces, and are axially movable in rela.- tion thereto, said first and said second wedges being attached to said sleeve.

^ 18. A free-wheeling clutch comprising a driving part and av driven part in coaxial arrangement,

at least one jamming member between said parts,

said jamming member having a free position and one jamming position in front and one jamming position behind its free position in the direction of rotation, a first resilient means arranged in front and a second resilient means arranged in the rear of4 said jamming member, one end of each of said resilient means being constantly in operative engagement with said jamming member, a pressure member for the other end of one of said resilient means, said pressure member being rigidly connected to one of said clutch parts, and externally controlled means for altering the tension of the other one of said resilient means. Y

STEFAN FISCHER. 

